p66Shc aging protein in control of fibroblasts cell fate

Endoplasmic Reticulum-Mitochondria Contacts Modulate Reactive Oxygen Species-Mediated Signaling and Oxidative Stress in Brain Disorders: The Key Role of Sigma-1 Receptor

Significance: Mitochondria-Associated Membranes (MAMs) are highly dynamic endoplasmic reticulum (ER)-mitochondria contact sites that, due to the transfer of lipids and Ca2+ between these organelles, modulate several physiologic processes, such as ER stress response, mitochondrial bioenergetics and fission/fusion events, autophagy, and inflammation. In addition, these contacts are implicated in the modulation of the cellular redox status since several MAMs-resident proteins are involved in the generation of reactive oxygen species (ROS), which can act as both signaling mediators and deleterious molecules, depending on their intracellular levels. Recent Advances: In the past few years, structural and functional alterations of MAMs have been associated with the pathophysiology of several neurodegenerative diseases that are closely associated with the impairment of several MAMs-associated events, including perturbation of the redox state on the accumulation of high ROS levels. Critical Issues: Inter-organelle contacts must be tightly regulated to preserve cellular functioning by maintaining Ca2+ and protein homeostasis, lipid metabolism, mitochondrial dynamics and energy production, as well as ROS signaling. Simultaneously, these contacts should avoid mitochondrial Ca2+ overload, which might lead to energetic deficits and deleterious ROS accumulation, culminating in oxidative stress-induced activation of apoptotic cell death pathways, which are common features of many neurodegenerative diseases. Future Directions: Given that Sig-1R is an ER resident chaperone that is highly enriched at the MAMs and that controls ER to mitochondria Ca2+ flux, as well as oxidative and ER stress responses, its potential as a therapeutic target for neurodegenerative diseases such as Amyotrophic Lateral Sclerosis, Alzheimer, Parkinson, and Huntington diseases should be further explored. Antioxid. Redox Signal. 37, 758-780.

Oxidative stress - Complex pathological issues concerning the hallmark of cardiovascular and metabolic disorders

Oxidative stress is a complex biological process characterized by the excessive production of reactive oxygen species (ROS) that act as destroyers of the REDOX balance in the body and, implicitly, inducing oxidative damage. All the metabolisms are impaired in oxidative stress and even nucleic acid balance is influenced. ROS will promote structural changes of the tissues and organs due to interaction with proteins and phospholipids. The constellation of the cardiovascular risk factors (CVRFs) will usually develop in subjects with predisposition to cardiac disorders. Oxidative stress is usually related with hypertension (HTN), diabetes mellitus (DM), obesity and cardiovascular diseases (CVDs) like coronary artery disease (CAD), cardiomyopathy or heart failure (HF), that can develop in subjects with the above-mentioned diseases. Elements describing the complex relationship between CVD and oxidative stress should be properly explored and described because prevention may be the optimal approach. Our paper aims to expose in detail the complex physiopathology of oxidative stress in CVD occurrence and novelties regarding the phenomenon. Biomarkers assessing oxidative stress or therapy targeting specific pathways represent a major progress that actually change the outcome of subjects with CVD. New antioxidants therapy specific for each CVD represents a captivating and interesting future perspective with tremendous benefits on subject's outcome.

Senescence-induced inflammation: an important player and key therapeutic target in atherosclerosis

Inflammation is a hallmark and potent driver of pathological vascular remodelling in atherosclerosis. However, current anti-inflammatory therapeutic strategies have shown mixed results. As an alternative perspective on the conundrum of chronic inflammation emerging evidence points towards a small subset of senescent cells as a critical player and central node driving atherosclerosis. Senescent cells belonging to various cell types are a dominant and chronic source of a large array of pro-inflammatory cytokines and various additional plaque destabilizing factors, being involved with various aspects of atherosclerosis pathogenesis. Antagonizing these key agitators of local chronic inflammation and plaque instability may provide a causative and multi-purpose therapeutic strategy to treat atherosclerosis. Anti-senescence treatment options with translational potential are currently in development. However, several questions and challenges remain to be addressed before these novel treatment approaches may enter the clinical setting.

Modulation of mitochondrial dysfunction-related oxidative stress in fibroblasts of patients with Leigh syndrome by inhibition of prooxidative p66Shc pathway

The mitochondrial respiratory chain, and in particular, complex I, is a major source of reactive oxygen species (ROS) in cells. Elevated levels of ROS are associated with an imbalance between the rate of ROS formation and the capacity of the antioxidant defense system. Increased ROS production may lead to oxidation of DNA, lipids and proteins and thus can affect fundamental cellular processes. The aim of this study was to investigate the magnitude of intracellular oxidative stress in fibroblasts of patients with Leigh syndrome with defined mutations in complex I. Moreover, we hypothesized that activation of the p66Shc protein (phosphorylation of p66Shc at Ser36 by PKCβ), being part of the oxidative stress response pathway, is partially responsible for the increased ROS production in cells with dysfunctional complex I. Characterization of bioenergetic parameters and ROS production showed that the cellular model of Leigh syndrome is described by increased intracellular oxidative stress and oxidative damage to DNA and proteins, which correlate with increased p66Shc phosphorylation at Ser36. Treatment of patients' fibroblasts with hispidin (an inhibitor of the protein kinase PKCβ), in addition to decreasing ROS production and intracellular oxidative stress, resulted in restoration of complex I activity.

Isolation of Endoplasmic Reticulum, Mitochondria, and Mitochondria-Associated Membrane and Detergent Resistant Membrane Fractions from Transfected Cells and from Human Cytomegalovirus-Infected Primary Fibroblasts

Increasingly mechanistic virology studies require dependable and sensitive methods for isolating purified organelles containing functional cellular sub-domains. The mitochondrial network is, in part, closely apposed to the endoplasmic reticulum (ER). The mitochondria-associated membrane (MAM) fraction provides direct physical contact between the ER and mitochondria. Characterization of the dual localization and trafficking of human cytomegalovirus (HCMV) UL37 proteins required establishing protocols in which the ER and mitochondria could be reliably separated. Because of its documented role in lipid and ceramide transfer from the ER to mitochondria, a method to purify MAM from infected cells was also developed. Two robust procedures were developed to efficiently isolate mitochondria, ER, and MAM fractions while providing substantial protein yields from HCMV-infected primary fibroblasts and from transfected HeLa cells. Furthermore, this unit includes protocols for isolation of detergent resistant membranes from subcellular fractions as well as techniques that allow visualization of the mitochondrial network disruption that occurs in permissively infected cells by their optimal resolution in Percoll gradients.

The Interplay Between Respiratory Supercomplexes and ROS in Aging

SIGNIFICANCE

The molecular mechanism of aging is still vigorously debated, although a general consensus exists that mitochondria are significantly involved in this process. However, the previously postulated role of mitochondrial-derived reactive oxygen species (ROS) as the damaging agents inducing functional loss in aging has fallen out of favor in the recent past. In this review, we critically examine the role of ROS in aging in the light of recent advances on the relationship between mitochondrial structure and function.

RECENT ADVANCES

The functional mitochondrial respiratory chain is now recognized as a reflection of the dynamic association of respiratory complexes in the form of supercomplexes (SCs). Besides providing kinetic advantage (channeling), SCs control ROS generation by the respiratory chain, thus providing a means to regulate ROS levels in the cell. Depending on their concentration, these ROS are either physiological signals essential for the life of the cell or toxic species that damage cell structure and functions.

CRITICAL ISSUES

We propose that under physiological conditions the dynamic nature of SCs reversibly controls the generation of ROS as signals involved in mitochondrial-nuclear communication. During aging, there is a progressive loss of control of ROS generation so that their production is irreversibly enhanced, inducing a vicious circle in which signaling is altered and structural damage takes place.

FUTURE DIRECTIONS

A better understanding on the forces affecting SC association would allow the manipulation of ROS generation, directing these species to their physiological signaling role.

The interplay between p66Shc, reactive oxygen species and cancer cell metabolism

The adaptor protein p66Shc links membrane receptors to intracellular signalling pathways and has the potential to respond to energy status changes and regulate mitogenic signalling. Initially reported to mediate growth signals in normal and cancer cells, p66Shc has also been recognized as a pro-apoptotic protein involved in the cellular response to oxidative stress. Moreover, it is a key element in processes such as cancer cell proliferation, tumor progression, metastasis and metabolic reprogramming. Recent findings on the role of p66Shc in the above-mentioned processes have been obtained through the use of various tumor cell types, including prostate, breast, ovarian, lung, colon, skin and thyroid cancer cells. Interestingly, the impact of p66Shc on the proliferation rate was mainly observed in prostate tumors, while its impact on metastasis was mainly found in breast cancers. In this review, we summarize the current knowledge about the possible roles of p66Shc in different cancers.

Effects of baicalin against UVA-induced photoaging in skin fibroblasts

Ultraviolet A (UVA) radiation contributes to skin photoaging. Baicalin, a plant-derived flavonoid, effectively absorbs UV rays and has been shown to have anti-oxidant and anti-inflammatory properties that may delay the photoaging process. In the current study, cultured human skin fibroblasts were incubated with 50 μg/ml baicalin 24 hours prior to 10 J/cm(2) UVA irradiation. In order to examine the efficacy of baicalin treatment in delaying UVA-induced photoaging, we investigated aging-related markers, cell cycle changes, anti-oxidant activity, telomere length, and DNA damage markers. UVA radiation caused an increased proportion of β-Gal positive cells and reduced telomere length in human skin fibroblasts. In addition, UVA radiation inhibited TGF-β1 secretion, induced G1 phase arrest, reduced SOD and GSH-Px levels, increased MDA levels, enhanced the expression of MMP-1, TIMP-1, p66, p53, and p16 mRNA, reduced c-myc mRNA expression, elevated p53 and p16 protein expression, and reduced c-myc protein expression. Baicalin treatment effectively protected human fibroblasts from these UVA radiation-induced aging responses, suggesting that the underlying mechanism involves the inhibition of oxidative damage and regulation of the expression of senescence-related genes, including those encoding for p53, p66(Shc) and p16.

Oxidative stress in cardiovascular diseases and obesity: role of p66Shc and protein kinase C

Reactive oxygen species (ROS) are a byproduct of the normal metabolism of oxygen and have important roles in cell signalling and homeostasis. An imbalance between ROS production and the cellular antioxidant defence system leads to oxidative stress. Environmental factors and genetic interactions play key roles in oxidative stress mediated pathologies. In this paper, we focus on cardiovascular diseases and obesity, disorders strongly related to each other; in which oxidative stress plays a fundamental role. We provide evidence of the key role played by p66(Shc) protein and protein kinase C (PKC) in these pathologies by their intracellular regulation of redox balance and oxidative stress levels. Additionally, we discuss possible therapeutic strategies aimed at attenuating the oxidative damage in these diseases.

Argirein alleviates corpus cavernosum dysfunction by suppressing pro-inflammatory factors p66Shc and ER stress chaperone Bip in diabetic rats

Objectives

The aim was to investigate whether argirein, which releases rhein and l-arginine after medication, could improve erectile dysfunction (ED) in diabetic rats through normalising the abnormalities of nitric oxide synthase (NOS), p66Shc and immunoglobulin heavy-chain binding protein (Bip), in the corpus cavernosum (CC).

Methods

SD rats were randomly divided into six groups. Except for the control group, rats were injected with streptozotocin (STZ) (60 mg/kg, i.p.) once. During weeks 5–8 following STZ injection, except for STZ-injected untreated rats, others were treated with aminoguanidine (AMG; 100 mg/kg/day, i.g.), or argirein at three doses (50, 100 and 200 mg/kg/day, i.g.). The vascular activity and biomarkers of the cavernosum were examined.

Key findings

Constrictive and dilative activity was abnormal in the CC, associated with decreased nitric oxide (NO) in serum in the diabetic (DM) group. Increased expression of p66Shc, Bip and inducible nitric oxide synthase (iNOS) and decreased endothelial nitric oxide synthase (eNOS) in the CC were significant in DM rats. Argirein and AMG improved these abnormities significantly.

Conclusions

We concluded that vascular activity of the cavernosal tissue was impaired due to upregulated p66Shc and Bip in the diabetic CC. Argirein alleviates the vascular dysfunction of the CC by suppressing these upregulated pro-inflammatory proteins caused by diabetic lesions.